力扣：21. 合并两个有序链表

LeetCode/src/main/java/com/code/leet/study/t20210205/MergeTwoLists.java

@@ -0,0 +1,21 @@
+package com.code.leet.study.t20210205;
+
+import com.code.leet.entiy.ListNode;
+
+public class MergeTwoLists {
+    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
+        if (l1 == null) {
+            return l2;
+        }
+        if (l2 == null) {
+            return l1;
+        }
+        if (l1.val < l2.val) {
+            l1.next = mergeTwoLists(l1.next, l2);
+            return l1;
+        } else {
+            l2.next = mergeTwoLists(l1, l2.next);
+            return l2;
+        }
+    }
+}